1. Technical Field
The present inventive subject matter relates to semiconductor devices and methods of fabricating the same and, more particularly, to MIM capacitors, semiconductor devices including MIM capacitors, and methods of fabricating the same.
2. Description of the Related Art
Generally, as the integration density of semiconductor devices, e.g., dynamic random access memory (DRAM) devices, increases, the area of a unit cell decreases, and the area occupied by a capacitor also decreases. Due to this reduction in the area of the capacitor, it becomes more problematic to fabricate a capacitor having a desired capacitance. Accordingly, to support greater integration density in semiconductor devices, there is a need for improved structures that may provide desirable capacitance.
If the thickness of a dielectric film used in a capacitor is reduced in order to increase capacitance, leakage current characteristics may be deteriorated. Therefore, a dielectric film having a high dielectric constant, i.e., a high dielectric film, may be employed. If a high dielectric film is used in a capacitor and a low dielectric film is formed between the high dielectric film and a polysilicon film of an upper electrode, and a desired capacitance may not be obtained.
Accordingly, metal-insulator-metal (MIM) capacitors have been introduced to replace metal-insulator-semiconductor (MIS) capacitors. However, in the metal-insulator-metal (MIM) capacitor, a high dielectric film may react with the upper electrode to reduce the capacitance. Techniques for reducing such reactions may increase the resistance of the upper electrode, which may degrade performance of the semiconductor device.